Tested in Extjs 4.1.1 and 4.1.2, IE9 and Chrome.
Window "constrain:true" inside another main window, a problem restoring its previous position after restore main window.
Steps to reproduce:
1- Take the window.js example (extjs examples/window)
2- Put "maximizable:true," to the win2 window.
3- Open the example in the browser
4- Maximize win2
5- Move one window inside it to the left
6- Restore win2
The window inside win2 doesn't restore your position correctly.